There's vast differences between tourneys and ring games online but the biggest four:

1) "You're broke you're done/They're broke they're done." Good players as a whole will play much tighter at the opening of tourneys than the player that doesn't realize this. But they only get to make a few mistakes. As a result of this "You're broke you're done" bluffing and blind stealing occurs later on when largely tighter players have survived.

2) The pressure of blind/ante increase. You mention this in passing, as in you know that, but this is the singlemost important difference. You can camp until your heart's content in a ring game (And at .05/.10 you should camp like crazy, the people at those stakes are madmen.) you do that in a tourney past the first five levels and you're just dead money, slightly higher placing dead money, but dead money nonetheless.

3) Stack size. Stack size does not matter in ring games, in tournaments stack size even outranks position in how you measure a hand. In ring games a good hand is a good hand and a bad hand is a bad hand, period, as modified by position and table. But your stack size never really matters too much since you should either be up or reloaded close to full. (Or you're doing something wrong.) Likewise you're not measuring the same "gap" with opponents because their stacks are again relative, they can reload at any time.

4) Shifting gears. Tournament play is measured less by the hands you get and more by your dexterity in shifting gears. In a tourney, particularly a big MTT you encounter every single type of table condition and stack condition on the way to the final table. You'll hit tight tables, loose tables, big stacks, small stacks, the whole gamut. if you have two average stacks behind you that look like they're camping for big hands then you must shift loose and start thieving their blinds to survive, if you have two huge stacks behind you re-raisnig everything then you're going to have to wait for a monster. Moreover, a table with the same people at it for a half hour straight can have its geography shift dramatically in the course of 45 minutes as blinds and antes change and chips are moved around. Though you'll need to use different styles in ring games at higher limits, you're not likely to be changing styles 6 times in an hour, but in a tourney you're going to be doing more than that.

Sklansky wrote an article about the differences between live and tourney play, not quite the same online, but decent reference.

http://www.twoplustwo.com/magazine/i...sklansky1.html